<?php
/// library functions for messaging


define ('MESSAGE_SHORTLENGTH', 300);
define ('MESSAGE_WINDOW', true);		  // We are in a message window (so don't pop up a new one!)

if (!isset($CFG->message_contacts_refresh)) {  // Refresh the contacts list every 60 seconds
	$CFG->message_contacts_refresh = 60;
}
if (!isset($CFG->message_chat_refresh)) {	  // Look for new comments every 5 seconds
	$CFG->message_chat_refresh = 5;
}
if (!isset($CFG->message_offline_time)) {
	$CFG->message_offline_time = 300;
}


function message_print_contacts() {
	global $USER, $CFG;

	$timetoshowusers = 300; //Seconds default
	if (isset($CFG->block_online_users_timetosee)) {
		$timetoshowusers = $CFG->block_online_users_timetosee * 60;
	}

	// time which a user is counting as being active since
	$timefrom = time()-$timetoshowusers;

	// people in our contactlist who are online
	$onlinecontacts  = array();
	// people in our contactlist who are offline
	$offlinecontacts = array();
	// people who are not in our contactlist but have sent us a message
	$strangers	   = array();


	// get all in our contactlist who are not blocked in our contact list 
	// and count messages we have waiting from each of them
	$contactsql = "SELECT u.id, u.firstname, u.lastname, u.picture, 
						  u.imagealt, u.lastaccess, count(m.id) as messagecount
				   FROM {$CFG->prefix}message_contacts mc
				   JOIN {$CFG->prefix}user u
					  ON u.id = mc.contactid
				   LEFT OUTER JOIN {$CFG->prefix}message m
					  ON m.useridfrom = mc.contactid
					  AND m.useridto = {$USER->id}
				   WHERE mc.userid = {$USER->id}
						 AND mc.blocked = 0 
				   GROUP BY u.id, u.firstname, u.lastname, u.picture,
							u.imagealt, u.lastaccess
				   ORDER BY u.firstname ASC;";

	if($rs = get_recordset_sql($contactsql)){
		while($rd = rs_fetch_next_record($rs)){

			if($rd->lastaccess >= $timefrom){
				// they have been active recently, so are counted online
				$onlinecontacts[] = $rd;
			}else{
				$offlinecontacts[] = $rd;
			}
		}
		unset($rd);
		rs_close($rs);
	}


	// get messages from anyone who isn't in our contact list and count the number
	// of messages we have from each of them
	$strangersql = "SELECT u.id, u.firstname, u.lastname, u.picture, 
						   u.imagealt, u.lastaccess, count(m.id) as messagecount
					FROM {$CFG->prefix}message m
					JOIN {$CFG->prefix}user u 
						ON u.id = m.useridfrom
					LEFT OUTER JOIN {$CFG->prefix}message_contacts mc
						ON mc.contactid = m.useridfrom AND 
						   mc.userid = m.useridto
					WHERE mc.id IS NULL AND m.useridto = {$USER->id} 
					GROUP BY u.id, u.firstname, u.lastname, u.picture,
							 u.imagealt, u.lastaccess
					ORDER BY u.firstname ASC;";

	if($rs = get_recordset_sql($strangersql)){
		while($rd= rs_fetch_next_record($rs)){
			$strangers[] = $rd;
		}
		unset($rd);
		rs_close($rs);
	}

	$countonlinecontacts  = count($onlinecontacts);
	$countofflinecontacts = count($offlinecontacts);
	$countstrangers	   = count($strangers);

	if ($countonlinecontacts + $countofflinecontacts == 0) {
		echo '<div class="heading">';
		print_string('contactlistempty', 'message');
		echo '</div>';
		echo '<div class="note">';
		print_string('addsomecontacts', 'message', $CFG->wwwroot.'/message/index.php?tab=search');
		echo '</div>';
	}

	echo '<table id="message_contacts" class="boxaligncenter" cellspacing="2" cellpadding="0" border="0">';

	if($countonlinecontacts) {
		/// print out list of online contacts

		echo '<tr><td colspan="3" class="heading">';
		echo get_string('onlinecontacts', 'message', $countonlinecontacts);
		echo '</td></tr>';

		foreach ($onlinecontacts as $contact) {
			message_print_contactlist_user($contact);
		}
	}
	echo '<tr><td colspan="3">&nbsp;</td></tr>';

	if ($countofflinecontacts) {
		/// print out list of offline contacts

		echo '<tr><td colspan="3" class="heading">';
		echo get_string('offlinecontacts', 'message', $countofflinecontacts);
		echo '</td></tr>';

		foreach ($offlinecontacts as $contact) {
			message_print_contactlist_user($contact);
		}
		echo '<tr><td colspan="3">&nbsp;</td></tr>';
	}

	/// print out list of incoming contacts
	if ($countstrangers) {
		echo '<tr><td colspan="3" class="heading">';
		echo get_string('incomingcontacts', 'message', $countstrangers);
		echo '</td></tr>';

		foreach ($strangers as $stranger) {
			message_print_contactlist_user($stranger, false);
		}
	}

	echo '</table>';

	if ($countstrangers && ($countonlinecontacts + $countofflinecontacts == 0)) {  // Extra help
		echo '<div class="note">(';
		print_string('addsomecontactsincoming', 'message');
		echo ')</div>';
	}

	echo '<br />';

	$autorefresh = '<p align="center" class="note">'.get_string('pagerefreshes', 'message', $CFG->message_contacts_refresh).'</p>';
	$autorefresh = addslashes_js($autorefresh); // js escaping

	// gracefully degrade JS autorefresh
	echo '<script type="text/javascript">
//<![CDATA[
document.write("'.$autorefresh.'")
//]]>
</script>';
	echo '<noscript><div class="button aligncenter">';
	echo print_single_button('index.php', false, get_string('refresh'));
	echo '</div></noscript>';
}


/// $messagearray is an array of objects
/// $field is a valid property of object
/// $value is the value $field should equal to be counted
/// if $field is empty then return count of the whole array
/// if $field is non-existent then return 0;
function message_count_messages($messagearray, $field='', $value='') {
	if (!is_array($messagearray)) return 0;
	if ($field == '' or empty($messagearray)) return count($messagearray);

	$count = 0;
	foreach ($messagearray as $message) {
		$count += ($message->$field == $value) ? 1 : 0;
	}
	return $count;
}


function message_print_search() {
	global $USER;

	if ($frm = data_submitted()) {

		message_print_search_results($frm);

	} else {
/*
/// unfinished buggy code disabled in search.html anyway
		// find all courses this use has readallmessages capabilities in
		if ($teachers = get_user_capability_course('moodle/site:readallmessages')) {
			$courses = get_courses('all', 'c.sortorder ASC', 'c.id, c.shortname');
			$cs = '<select name="courseselect">';
			foreach ($teachers as $tcourse) {
				$cs .= "<option value=\"$tcourse->course\">".$courses[$tcourse->id]->shortname."</option>\n";
			}
			$cs .= '</select>';
		}
*/
		include('search.html');
	}
}

function message_print_settings() {
	global $USER;

	if ($frm = data_submitted() and confirm_sesskey()) {

		$pref = array();
		$pref['message_showmessagewindow'] = (isset($frm->showmessagewindow)) ? '1' : '0';
		$pref['message_beepnewmessage'] = (isset($frm->beepnewmessage)) ? '1' : '0';
		$pref['message_blocknoncontacts'] = (isset($frm->blocknoncontacts)) ? '1' : '0';
		$pref['message_usehtmleditor'] = (isset($frm->usehtmleditor)) ? '1' : '0';
		$pref['message_noframesjs'] = (isset($frm->noframesjs)) ? '1' : '0';
		$pref['message_emailmessages'] = (isset($frm->emailmessages)) ? '1' : '0';
		$pref['message_emailtimenosee'] = ((int)$frm->emailtimenosee > 0) ? (int)$frm->emailtimenosee : '10';
		$pref['message_emailaddress'] = (!empty($frm->emailaddress)) ? $frm->emailaddress : $USER->email;
		$pref['message_emailformat'] = (isset($frm->emailformat)) ? $frm->emailformat : FORMAT_PLAIN;

		set_user_preferences($pref);

		redirect('index.php', get_string('settingssaved', 'message'), 1);
	}

	$cbshowmessagewindow = (get_user_preferences('message_showmessagewindow', 1) == '1') ? 'checked="checked"' : '';
	$cbbeepnewmessage = (get_user_preferences('message_beepnewmessage', 0) == '1') ? 'checked="checked"' : '';
	$cbblocknoncontacts = (get_user_preferences('message_blocknoncontacts', 0) == '1') ? 'checked="checked"' : '';
	$cbusehtmleditor = (get_user_preferences('message_usehtmleditor', 0) == '1') ? 'checked="checked"' : '';
	$cbnoframesjs = (get_user_preferences('message_noframesjs', 0) == '1') ? 'checked="checked"' : '';
	$cbemailmessages = (get_user_preferences('message_emailmessages', 1) == '1') ? 'checked="checked"' : '';
	$txemailaddress = get_user_preferences('message_emailaddress', $USER->email);
	$txemailtimenosee = get_user_preferences('message_emailtimenosee', 10);
	$format_select = choose_from_menu( array(FORMAT_PLAIN => get_string('formatplain'),
											 FORMAT_HTML  => get_string('formathtml')),
									   'emailformat',
									   get_user_preferences('message_emailformat', FORMAT_PLAIN),
									   false, '', '0', true );

	include('settings.html');
}



function message_add_contact($contactid, $blocked=0) {
	global $USER;

	if (!record_exists('user', 'id', $contactid)) { // invalid userid
		return false;
	}

	if (($contact = get_record('message_contacts', 'userid', $USER->id, 'contactid', $contactid)) !== false) {
	/// record already exists - we may be changing blocking status

		if ($contact->blocked !== $blocked) {
		/// change to blocking status
			$contact->blocked = $blocked;
			return update_record('message_contacts', $contact);
		} else {
		/// no changes to blocking status
			return true;
		}

	} else {
	/// new contact record
		unset($contact);
		$contact->userid = $USER->id;
		$contact->contactid = $contactid;
		$contact->blocked = $blocked;
		return insert_record('message_contacts', $contact, false);
	}
}

function message_remove_contact($contactid) {
	global $USER;
	return delete_records('message_contacts', 'userid', $USER->id, 'contactid', $contactid);
}

function message_unblock_contact($contactid) {
	global $USER;
	return delete_records('message_contacts', 'userid', $USER->id, 'contactid', $contactid);
}

function message_block_contact($contactid) {
	return message_add_contact($contactid, 1);
}

function message_get_contact($contactid) {
	global $USER;
	return get_record('message_contacts', 'userid', $USER->id, 'contactid', $contactid);
}



function message_print_search_results($frm) {
	global $USER, $CFG;

	echo '<div class="mdl-align">';

	/// search for person
	if (!empty($frm->personsubmit) and !empty($frm->name)) {

		if (optional_param('mycourses', 0, PARAM_BOOL)) {
			$users = array();
			$mycourses = get_my_courses($USER->id);
			foreach ($mycourses as $mycourse) {
				if (is_array($susers = message_search_users($mycourse->id, $frm->name))) {
					foreach ($susers as $suser) $users[$suser->id] = $suser;
				}
			}
		} else {
			$users = message_search_users(SITEID, $frm->name);
		}

		if (!empty($users)) {
			echo '<strong>'.get_string('userssearchresults', 'message', count($users)).'</strong>';
			echo '<table class="message_users">';
			foreach ($users as $user) {

				if ( $user->contactlistid )  {
					if ($user->blocked == 0) { /// not blocked
						$strcontact = message_contact_link($user->id, 'remove', true);
						$strblock   = message_contact_link($user->id, 'block', true);
					} else { // blocked
						$strcontact = message_contact_link($user->id, 'add', true);
						$strblock   = message_contact_link($user->id, 'unblock', true);
					}
				} else {
					$strcontact = message_contact_link($user->id, 'add', true);
					$strblock   = message_contact_link($user->id, 'block', true);
				}
				$strhistory = message_history_link($user->id, 0, true, '', '', 'icon');

				echo '<tr><td class="pix">';
				print_user_picture($user, SITEID, $user->picture, 20, false, true, 'userwindow');
				echo '</td>';
				echo '<td class="contact">';
				link_to_popup_window("/message/discussion.php?id=$user->id", "message_$user->id", fullname($user),
									 500, 500, get_string('sendmessageto', 'message', fullname($user)),
									 'menubar=0,location=0,status,scrollbars,resizable,width=500,height=500');

				echo '</td>';

				echo '<td class="link">'.$strcontact.'</td>';
				echo '<td class="link">'.$strblock.'</td>';
				echo '<td class="link">'.$strhistory.'</td>';
				echo '</tr>';
			}
			echo '</table>';

		} else {
			notify(get_string('nosearchresults', 'message'));
		}


	/// search messages for keywords
	} else if (!empty($frm->keywordssubmit) and !empty($frm->keywords)) {
		$keywordstring = clean_text(trim($frm->keywords));
		$keywords = explode(' ', $keywordstring);
		$tome	 = false;
		$fromme   = false;
		$courseid = 'none';

		switch ($frm->keywordsoption) {
			case 'tome':
				$tome   = true;
				break;
			case 'fromme':
				$fromme = true;
				break;
			case 'allmine':
				$tome   = true;
				$fromme = true;
				break;
			case 'allusers':
				$courseid = SITEID;
				break;
			case 'courseusers':
				$courseid = $frm->courseid;
				break;
			default:
				$tome   = true;
				$fromme = true;
		}

		if (($messages = message_search($keywords, $fromme, $tome, $courseid)) !== false) {

		/// get a list of contacts
			if (($contacts = get_records('message_contacts', 'userid', $USER->id, '', 'contactid, blocked') ) === false) {
				$contacts = array();
			}

		/// print heading with number of results
			echo '<p class="heading">'.get_string('keywordssearchresults', 'message', count($messages)).' ("'.s($keywordstring).'")</p>';

		/// print table headings
			echo '<table class="searchresults" cellspacing="0">';
			echo '<tr>';
			echo '<td><strong>'.get_string('from').'</strong></td>';
			echo '<td><strong>'.get_string('to').'</strong></td>';
			echo '<td><strong>'.get_string('message', 'message').'</strong></td>';
			echo '<td><strong>'.get_string('timesent', 'message').'</strong></td>';
			echo "</tr>\n";

			$blockedcount = 0;
			$dateformat = get_string('strftimedatetimeshort');
			$strcontext = get_string('context', 'message');
			foreach ($messages as $message) {

			/// ignore messages to and from blocked users unless $frm->includeblocked is set
				if (!optional_param('includeblocked', 0, PARAM_BOOL) and (
					  ( isset($contacts[$message->useridfrom]) and ($contacts[$message->useridfrom]->blocked == 1)) or
					  ( isset($contacts[$message->useridto]  ) and ($contacts[$message->useridto]->blocked   == 1))
												)
				   ) {
					$blockedcount ++;
					continue;
				}

			/// load up user to record
				if ($message->useridto !== $USER->id) {
					$userto = get_record('user', 'id', $message->useridto);
					$tocontact = (array_key_exists($message->useridto, $contacts) and
									($contacts[$message->useridto]->blocked == 0) );
					$toblocked = (array_key_exists($message->useridto, $contacts) and
									($contacts[$message->useridto]->blocked == 1) );
				} else {
					$userto = false;
					$tocontact = false;
					$toblocked = false;
				}

			/// load up user from record
				if ($message->useridfrom !== $USER->id) {
					$userfrom = get_record('user', 'id', $message->useridfrom);
					$fromcontact = (array_key_exists($message->useridfrom, $contacts) and
									($contacts[$message->useridfrom]->blocked == 0) );
					$fromblocked = (array_key_exists($message->useridfrom, $contacts) and
									($contacts[$message->useridfrom]->blocked == 1) );
				} else {
					$userfrom = false;
					$fromcontact = false;
					$fromblocked = false;
				}

			/// find date string for this message
				$date = usergetdate($message->timecreated);
				$datestring = $date['year'].$date['mon'].$date['mday'];

			/// print out message row
				echo '<tr valign="top">';
				echo '<td class="contact">';
				message_print_user($userfrom, $fromcontact, $fromblocked);
				echo '</td>';
				echo '<td class="contact">';
				message_print_user($userto, $tocontact, $toblocked);
				echo '</td>';
				echo '<td class="summary">'.message_get_fragment($message->message, $keywords);
				echo '<br /><div class="link">';
				message_history_link($message->useridto, $message->useridfrom, false,
									 $keywordstring, 'm'.$message->id, $strcontext);
				echo '</div>';
				echo '</td>';
				echo '<td class="date">'.userdate($message->timecreated, $dateformat).'</td>';
				echo "</tr>\n";
			}


			if ($blockedcount > 0) {
				echo '<tr><td colspan="4" align="center">'.get_string('blockedmessages', 'message', $blockedcount).'</td></tr>';
			}
			echo '</table>';

		} else {
			notify(get_string('nosearchresults', 'message'));
		}


	/// what the ????, probably an empty search string, duh!
	} else {
		notify(get_string('emptysearchstring', 'message'));
	}

	echo '<br />';
	print_single_button('index.php', array( 'tab' => 'search'), get_string('newsearch', 'message') );

	echo '</div>';
}


function message_print_user ($user=false, $iscontact=false, $isblocked=false) {
	global $USER;
	if ($user === false) {
		print_user_picture($USER, SITEID, $USER->picture, 20, false, true, 'userwindow');
	} else {
		print_user_picture($user, SITEID, $user->picture, 20, false, true, 'userwindow');
		echo '&nbsp;';
		if ($iscontact) {
			message_contact_link($user->id, 'remove');
		} else {
			message_contact_link($user->id, 'add');
		}
		echo '&nbsp;';
		if ($isblocked) {
			message_contact_link($user->id, 'unblock');
		} else {
			message_contact_link($user->id, 'block');
		}
		echo '<br />';

		link_to_popup_window("/message/discussion.php?id=$user->id", "message_$user->id",
							 fullname($user), 400, 400, get_string('sendmessageto', 'message', fullname($user)),
							 'menubar=0,location=0,status,scrollbars,resizable,width=500,height=500');
	}
}


/// linktype can be: add, remove, block, unblock
function message_contact_link($userid, $linktype='add', $return=false, $script="index.php?tab=contacts", $text=false) {
	global $USER, $CFG;

	static $str;

	if (empty($str->blockcontact)) {
	   $str->blockcontact   =  get_string('blockcontact', 'message');
	   $str->unblockcontact =  get_string('unblockcontact', 'message');
	   $str->removecontact  =  get_string('removecontact', 'message');
	   $str->addcontact	 =  get_string('addcontact', 'message');
	}

	$command = $linktype.'contact';
	$string  = $str->{$command};
	$alttext = $text ? '' : $string; 
	$text = $text ? '&nbsp;'.$string : '';

	switch ($linktype) {
		case 'block':
			$icon = '/t/go.gif';
			break;
		case 'unblock':
			$icon = '/t/stop.gif';
			break;
		case 'remove':
			$icon = '/t/user.gif';
			break;
		case 'add':
		default:
			$icon = '/t/usernot.gif';
	}

	$output = '<span class="'.$linktype.'">'.
			  '<a href="'.$script.'&amp;'.$command.'='.$userid.
			  '&amp;sesskey='.sesskey().'" title="'.s($string).'">'.
			  '<img src="'.$CFG->pixpath.$icon.'" class="iconsmall" alt="'.s($alttext).'" />'.
			  $text.'</a></span>';

	if ($return) {
		return $output;
	} else {
		echo $output;
		return true;
	}
}

function message_history_link($userid1, $userid2=0, $returnstr=false, $keywords='', $position='', $linktext='') {
	global $USER, $CFG;

	static $strmessagehistory;

	if (empty($strmessagehistory)) {
		$strmessagehistory = get_string('messagehistory', 'message');
	}

	if (!$userid2) {
		$userid2 = $USER->id;
	}
	if ($position) {
		$position = "#$position";
	}
	if ($keywords) {
		$keywords = "&search=".urlencode($keywords);
	}

	if ($linktext == 'icon') {  // Icon only
		$fulllink = '<img src="'.$CFG->pixpath.'/t/log.gif" class="iconsmall" alt="'.$strmessagehistory.'" />';
	} else if ($linktext == 'both') {  // Icon and standard name
		$fulllink = '<img src="'.$CFG->pixpath.'/t/log.gif" class="iconsmall" alt="" />';
		$fulllink .= '&nbsp;'.$strmessagehistory;
	} else if ($linktext) {	// Custom name
		$fulllink = $linktext;
	} else {				   // Standard name only
		$fulllink = $strmessagehistory;
	}

	$str = link_to_popup_window("/message/history.php?user1=$userid1&amp;user2=$userid2$keywords$position",
					"message_history_$userid1", $fulllink, 500, 500, $strmessagehistory,
					'menubar=0,location=0,status,scrollbars,resizable,width=500,height=500', true);

	$str = '<span class="history">'.$str.'</span>';

	if ($returnstr) {
		return $str;
	} else {
		echo $str;
		return true;
	}
}


/**
 * Search through course users
 *
 * If $coursid specifies the site course then this function searches
 * through all undeleted and confirmed users
 *
 * @uses $CFG, $USER
 * @uses SITEID
 * @param int $courseid The course in question.
 * @param string $searchtext ?
 * @param string $sort ?
 * @param string $exceptions ?
 * @return array  An array of {@link $USER} records.
 * @todo Finish documenting this function
 */
function message_search_users($courseid, $searchtext, $sort='', $exceptions='') {
	global $CFG, $USER;

	$fullname = sql_fullname();
	$LIKE	 = sql_ilike();

	if (!empty($exceptions)) {
		$except = ' AND u.id NOT IN ('. $exceptions .') ';
	} else {
		$except = '';
	}

	if (!empty($sort)) {
		$order = ' ORDER BY '. $sort;
	} else {
		$order = '';
	}

	$select = 'u.deleted = \'0\' AND u.confirmed = \'1\'';
	$fields = 'u.id, u.firstname, u.lastname, u.picture, u.imagealt, mc.id as contactlistid, mc.blocked';

	if (!$courseid or $courseid == SITEID) {
		return get_records_sql("SELECT $fields
					  FROM {$CFG->prefix}user u
					  LEFT OUTER JOIN {$CFG->prefix}message_contacts mc
					  ON mc.contactid = u.id AND mc.userid = {$USER->id} 
					  WHERE $select
						  AND ($fullname $LIKE '%$searchtext%')
						  $except $order");
	} else {

		$context = get_context_instance(CONTEXT_COURSE, $courseid);
		$contextlists = get_related_contexts_string($context);

		// everyone who has a role assignement in this course or higher
		$users = get_records_sql("SELECT $fields
								 FROM {$CFG->prefix}user u
								 JOIN {$CFG->prefix}role_assignments ra
								 ON ra.userid = u.id
								 LEFT OUTER JOIN {$CFG->prefix}message_contacts mc
								 ON mc.contactid = u.id AND mc.userid = {$USER->id} 
								 WHERE $select
									   AND ra.contextid $contextlists
									   AND ($fullname $LIKE '%$searchtext%')
									   $except $order");

		return $users;
	}
}




function message_search($searchterms, $fromme=true, $tome=true, $courseid='none', $userid=0) {
/// Returns a list of posts found using an array of search terms
/// eg   word  +word -word
///

	global $CFG, $USER;

	/// If no userid sent then assume current user
	if ($userid == 0) $userid = $USER->id;

	/// Some differences in SQL syntax
	$LIKE = sql_ilike();
	$NOTLIKE = 'NOT ' . $LIKE;
	if ($CFG->dbfamily == "postgres") {
		$REGEXP = "~*";
		$NOTREGEXP = "!~*";
	} else {
		$REGEXP = "REGEXP";
		$NOTREGEXP = "NOT REGEXP";
	}

	$messagesearch = "";

	foreach ($searchterms as $searchterm) {
		if (strlen($searchterm) < 2) {
			continue;
		}
	/// Under Oracle and MSSQL, trim the + and - operators and perform
	/// simpler LIKE search
		if ($CFG->dbfamily == 'oracle' || $CFG->dbfamily == 'mssql') {
			$searchterm = trim($searchterm, '+-');
		}

		if ($messagesearch) {
			$messagesearch .= " AND ";
		}

		if (substr($searchterm,0,1) == "+") {
			$searchterm = substr($searchterm,1);
			$messagesearch .= " m.message $REGEXP '(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)' ";
		} else if (substr($searchterm,0,1) == "-") {
			$searchterm = substr($searchterm,1);
			$messagesearch .= " m.message $NOTREGEXP '(^|[^a-zA-Z0-9])$searchterm([^a-zA-Z0-9]|$)' ";
		} else {
			$messagesearch .= " m.message $LIKE '%$searchterm%' ";
		}
	}

	if ($messagesearch == '') { // if only 1 letter words searched
		return false;
	}

	$messagesearch = "($messagesearch) ";


	/// There are several possibilities
	/// 1. courseid = SITEID : The admin is searching messages by all users
	/// 2. courseid = ??	 : A teacher is searching messages by users in
	///						one of their courses - currently disabled
	/// 3. courseid = none   : User is searching their own messages;
	///	a.  Messages from user
	///	b.  Messages to user
	///	c.  Messages to and from user

	if ($courseid == SITEID) { /// admin is searching all messages
		$m_read   = get_records_sql("SELECT m.id, m.useridto, m.useridfrom, m.message, m.timecreated
									 FROM {$CFG->prefix}message_read m
									 WHERE $messagesearch");
		$m_unread = get_records_sql("SELECT m.id, m.useridto, m.useridfrom, m.message, m.timecreated
									 FROM {$CFG->prefix}message m
									 WHERE $messagesearch");

		if ($m_read   === false) $m_read   = array();
		if ($m_unread === false) $m_unread = array();

	} elseif ($courseid !== 'none') {
		/// This has not been implemented due to security concerns

	} else {

		if	 ($fromme and $tome) $messagesearch .= "AND (m.useridfrom='$userid' OR m.useridto='$userid') ";
		elseif ($fromme)		   $messagesearch .= "AND m.useridfrom='$userid' ";
		elseif ($tome)			 $messagesearch .= "AND m.useridto='$userid' ";

		$m_read   = get_records_sql("SELECT m.id, m.useridto, m.useridfrom, m.message, m.timecreated
									 FROM {$CFG->prefix}message_read m
									 WHERE $messagesearch");
		$m_unread = get_records_sql("SELECT m.id, m.useridto, m.useridfrom, m.message, m.timecreated
									 FROM {$CFG->prefix}message m
									 WHERE $messagesearch");

		if ($m_read   === false) $m_read   = array();
		if ($m_unread === false) $m_unread = array();

	}

	/// The keys may be duplicated in $m_read and $m_unread so we can't
	/// do a simple concatenation
	$message = array();
	foreach ($m_read as $m) $messages[] = $m;
	foreach ($m_unread as $m) $messages[] = $m;


	return (empty($messages)) ? false : $messages;
}



/// Borrowed with changes from mod/forum/lib.php
function message_shorten_message($message, $minlength=0) {
// Given a post object that we already know has a long message
// this function truncates the message nicely to the first
// sane place between $CFG->forum_longpost and $CFG->forum_shortpost

	$i = 0;
	$tag = false;
	$length = strlen($message);
	$count = 0;
	$stopzone = false;
	$truncate = 0;
	if ($minlength == 0) $minlength = MESSAGE_SHORTLENGTH;


	for ($i=0; $i<$length; $i++) {
		$char = $message[$i];

		switch ($char) {
			case "<":
				$tag = true;
				break;
			case ">":
				$tag = false;
				break;
			default:
				if (!$tag) {
					if ($stopzone) {
						if ($char == '.' or $char == ' ') {
							$truncate = $i+1;
							break 2;
						}
					}
					$count++;
				}
				break;
		}
		if (!$stopzone) {
			if ($count > $minlength) {
				$stopzone = true;
			}
		}
	}

	if (!$truncate) {
		$truncate = $i;
	}

	return substr($message, 0, $truncate);
}


/*
 * Given a string and an array of keywords, this function looks
 * for the first keyword in the string, and then chops out a
 * small section from the text that shows that word in context.
 */
function message_get_fragment($message, $keywords) {

	$fullsize = 120;
	$halfsize = (int)($fullsize/2);

	$message = strip_tags($message);

	foreach ($keywords as $keyword) {  // Just get the first one
		if ($keyword !== '') {
			break;
		}
	}
	if (empty($keyword)) {   // None found, so just return start of message
		return message_shorten_message($message, 30);
	}

	$leadin = $leadout = '';

/// Find the start of the fragment
	$start = 0;
	$length = strlen($message);

	$pos = strpos($message, $keyword);
	if ($pos > $halfsize) {
		$start = $pos - $halfsize;
		$leadin = '...';
	}
/// Find the end of the fragment
	$end = $start + $fullsize;
	if ($end > $length) {
		$end = $length;
	} else {
		$leadout = '...';
	}

/// Pull out the fragment and format it

	$fragment = substr($message, $start, $end - $start);
	$fragment = $leadin.highlight(implode(' ',$keywords), $fragment).$leadout;
	return $fragment;
}


function message_get_history($user1, $user2) {
	$messages = get_records_select('message_read', "(useridto = '$user1->id' AND useridfrom = '$user2->id') OR
													(useridto = '$user2->id' AND useridfrom = '$user1->id')",
													'timecreated');
	if ($messages_new =  get_records_select('message', "(useridto = '$user1->id' AND useridfrom = '$user2->id') OR
													(useridto = '$user2->id' AND useridfrom = '$user1->id')",
													'timecreated')) {
		foreach ($messages_new as $message) {
			$messages[] = $message;
		}
	}
	return $messages;
}

function message_format_message(&$message, &$user, $format='', $keywords='', $class='other') {

	static $dateformat;

	if (empty($dateformat)) {
		if ($format) {
			$dateformat = $format;
		} else {
			$format = get_string('strftimedatetimeshort');
		}
	}
	$time = userdate($message->timecreated, $dateformat);
	$options->para = false;
	$messagetext = format_text($message->message, $message->format, $options);
	if ($keywords) {
		$messagetext = highlight($keywords, $messagetext);
	}
	return '<div class="message '.$class.'"><a name="m'.$message->id.'"></a><span class="author">'.s(fullname($user)).'</span> <span class="time">['.$time.']</span>: <span class="content">'.$messagetext.'</span></div>';
}

/*
 * Inserts a message into the database, but also forwards it
 * via other means if appropriate.
 */
function message_post_message($userfrom, $userto, $message, $format, $messagetype) {

	global $CFG, $SITE, $USER;

/// Set up current language to suit the receiver of the message
	$savelang = $USER->lang;
	
	if (!empty($userto->lang)) {
		$USER->lang = $userto->lang;
	}

/// Save the new message in the database

	$savemessage = NULL;
	$savemessage->useridfrom	= $userfrom->id;
	$savemessage->useridto	  = $userto->id;
	$savemessage->message	   = $message;
	$savemessage->format		= $format;
	$savemessage->timecreated   = time();
	$savemessage->messagetype   = 'direct';

	if ($CFG->messaging) {
		if (!$savemessage->id = insert_record('message', $savemessage)) {
			return false;
		}
		$emailforced = false;
	} else { // $CFG->messaging is not on, we need to force sending of emails
		$emailforced = true;
		$savemessage->id = true; 
	}

/// Check to see if anything else needs to be done with it

	$preference = (object)get_user_preferences(NULL, NULL, $userto->id);

	if ($emailforced || (!isset($preference->message_emailmessages) || $preference->message_emailmessages)) {  // Receiver wants mail forwarding
		if (!isset($preference->message_emailtimenosee)) {
			$preference->message_emailtimenosee = 10;
		}
		if (!isset($preference->message_emailformat)) {
			$preference->message_emailformat = FORMAT_HTML;
		}
		if ($emailforced || (time() - $userto->lastaccess) > ((int)$preference->message_emailtimenosee * 60)) { // Long enough

			$message = stripslashes_safe($message);
			$tagline = get_string('emailtagline', 'message', $SITE->shortname);

			$messagesubject = preg_replace('/\s+/', ' ', strip_tags($message)); // make sure it's all on one line
			$messagesubject = message_shorten_message($messagesubject, 30).'...';

			$messagetext = format_text_email($message, $format).
						   "\n\n--\n".$tagline."\n"."$CFG->wwwroot/message/index.php?popup=1";

			if (isset($preference->message_emailformat) and $preference->message_emailformat == FORMAT_HTML) {
				$messagehtml  = format_text($message, $format);
				// MDL-10294, do not print link if messaging is disabled
				if ($CFG->messaging) {
					$messagehtml .= '<hr /><p><a href="'.$CFG->wwwroot.'/message/index.php?popup=1">'.$tagline.'</a></p>';
				}
			} else {
				$messagehtml = NULL;
			}

			if (!empty($preference->message_emailaddress)) {
				$userto->email = $preference->message_emailaddress;   // Use custom messaging address
			}

			if (email_to_user($userto, $userfrom, $messagesubject, $messagetext, $messagehtml)) {
				$CFG->messagewasjustemailed = true;
			}

			sleep(3);
		}
	}

	$USER->lang = $savelang;  // restore original language

	return $savemessage->id;
}


/*
 * Returns a list of all user ids who have used messaging in the site
 * This was the simple way to code the SQL ... is it going to blow up
 * on large datasets?
 */
function message_get_participants() {

	global $CFG;

		return get_records_sql("SELECT useridfrom as id,1 FROM {$CFG->prefix}message
						   UNION SELECT useridto as id,1 FROM {$CFG->prefix}message
						   UNION SELECT useridfrom as id,1 FROM {$CFG->prefix}message_read
						   UNION SELECT useridto as id,1 FROM {$CFG->prefix}message_read
						   UNION SELECT userid as id,1 FROM {$CFG->prefix}message_contacts
						   UNION SELECT contactid as id,1 from {$CFG->prefix}message_contacts");
}

/**
 * Print a row of contactlist displaying user picture, messages waiting and 
 * block links etc
 * @param $contact contact object containing all fields required for print_user_picture()
 * @param $incontactlist is the user a contact of ours?
 */
function message_print_contactlist_user($contact, $incontactlist = true){
	$fullname  = fullname($contact);
	$fullnamelink  = $fullname;

	/// are there any unread messages for this contact?
	if ($contact->messagecount > 0 ){
		$fullnamelink = '<strong>'.$fullnamelink.' ('.$contact->messagecount.')</strong>';
	}


	if($incontactlist){
		$strcontact = message_contact_link($contact->id, 'remove', true);
		$strblock   = '';
	}else{
		$strcontact = message_contact_link($contact->id, 'add', true);
		$strblock   = '&nbsp;'. message_contact_link($contact->id, 'block', true);
	}

	$strhistory = message_history_link($contact->id, 0, true, '', '', 'icon');

	echo '<tr><td class="pix">';
	print_user_picture($contact, SITEID, $contact->picture, 20, false, true, 'userwindow');
	echo '</td>';
	echo '<td class="contact">';

	link_to_popup_window("/message/discussion.php?id=$contact->id", "message_$contact->id",
		$fullnamelink, 500, 500, get_string('sendmessageto', 'message', $fullname),
		'menubar=0,location=0,status,scrollbars,resizable,width=500,height=500');

	echo '</td>';
	echo '<td class="link">&nbsp;'.$strcontact.$strblock.'&nbsp;'.$strhistory.'</td>';
	echo '</tr>';
}

?>
